It's my understanding that brake lines can be ordered from MB dealers, but they are straight lengths and must be bent to fit.
Interesting info about copper and cunifer tubing.

I must replace some of my brake lines in the rear of an E320 wagon so I'm going to inventory my needs and place an order for some fittings and lines.
If the brake lines go well, I'll consider working on the SLS lines.
I hope this info helps others.